Rapid Alignment of Collagen Fibers in the Dermis of Undermined and Not Undermined Skin Stretched with a Skin-Stretching Device

Abstract

A controlled, quantitative histochemical study was performed in five piglets to establish changes in undermined and not undermined stretched skin. The skin was stretched with a stretching device for 30 minutes to close a large skin defect. On each flank of the piglet, at a standard position, 9 x 9-cm wounds were created under general anesthesia. On one flank, the surrounding skin was undermined cranially and caudally over a 10-centimeter area. Sections of skin biopsies obtained during stretching were stained with picrosirius red and studied with routine light microscopy and polarized light microscopy in combination with image analysis. The length of collagen fibers was analyzed as a parameter of changes in the dermis resulting from skin stretching. This newly developed quantitative method appeared to be valid, specific, and reproducible, allowing for objective determination of changes in the length of the fibers in the plain of the sections. Changes in the orientation of collagen fibers in the dermis as a result of skin stretching were thereby determined. Epidermal thickness did not change significantly under the influence of stretching forces in both undermined and not undermined skin. However, the orientation of the collagen fibers changed significantly as a result of skin stretching. In undermined wounds, parallel alignment and elongation of the fibers in the plane of the sections was already observed after 15 minutes of stretching. The fibers became aligned in the direction of the stretching force, perpendicular to the wound margin. After 30 minutes of stretching, the mean major axes of the collagen fibers were longest in the plane of the sections (p < 0.001). This meant that elongation and parallel alignment of the collagen fibers had occurred. Stretching of not undermined skin for 15 minutes resulted in significantly stronger parallel alignment in the plane of the sections as compared with undermined skin. This was less well defined after 30 minutes of stretching in not undermined skin. It is concluded that skin stretching with a skin-stretching device for 30 minutes results in significant histomorphological changes of collagen fibers in the dermis of both undermined and not undermined skin. The fibers realign rapidly as a result of stretching forces and become aligned in the direction of the stretching force, perpendicular to the wound margin. These dynamic changes in collagen fibers explain the significantly decreased wound closing tension resulting from skin stretching and explain how skin stretches beyond its inherent extensibility.

In vivo evaluation of human skin anisotropy by polarization-sensitive optical coherence tomography

“…It is known that the stretching of the skin promotes alignment of collagen fibers [9] [10,34]. We also speculate that internal force promotes the alignment of collagen fiber in the same direction, enhancing birefringence in this study.…”

Closure of large wounds using rubber bands in rabbits

“…When at rest, these collagen fibers are wavy and, with stretching, the undulations flatten, the fibers extending in the same direction of the traction. As the drift increases, a greater number of fibers get aligned, to form a structure of parallel collagen fibers, resistant to stretching 25,26 .…”

“…Hyperplasia also plays an important role in tissue growth and results from the continuous stretching of the skin, which responds with cell proliferation and tissue growth 27,28 . On the other hand, fast stretching under intense traction causes disruption of collagen fibers, culminating in the formation of stretch marks 26,28 . Excessive stretching can also cause distension and collapse of the small vessels of the skin, leading to ischemic necrosis of the edges of the wound and dehiscence 13,27 .…”

The TopClosure® 3S System, for skin stretching and a secure wound closure

“…As a result of skin stretching, wound closing tension decreases over time, allowing primary closure of relatively large defects [24]. Load cycling of skin implies an incremental increase in the length of the skin [25]. …”